With regard to the significant features of the present invention and other features relating thereto, it can be mentioned that there are known to the art different types of telephone exchanges which fulfil the aforesaid basic requirements regarding the function of the present invention.
The call transfer function required by the invention is known to the art and is included in many telephone exchanges, such as operator-manned subscriber exchanges. One such function is based on a facility which, during an on going call between a calling person, a first person, and a called person, a second person, such as a telephone operator, enables the second person to call a third person and transfer the call to this latter person so as to establish a call connection between the first person and the third person called by the second person without the second person being involved in a subsequent call exchange. This call transfer function is initiated by the calling person, the second person, by actuating the keypad of the telephone apparatus in a manner applicable to the telephone exchange concerned.
The second person is then released from the call connection established by the call transfer function directly between the first and the third person.
The AXE subscriber switching network retailed by Telefonaktiebolaget LM Ericsson, Stockholm, Sweden, under the designation "AXE-station" is one example of a telephone exchange that incorporates a call transfer facility.
With regard to the present state of techniques, particular reference can be made to the teachings of U.S. Pat. No. 5,432,840, in which there is described and illustrated a method and an arrangement for selective connection of a permanent subscriber apparatus to nearby mobile subscriber apparatus with the aid of exchange switching functions.
The reader is referred to this American patent publication for a more basic understanding of the present invention and related known techniques.